Light absorption enhancement in thin silicon film by embedded metallic nanoshells: erratum

Light absorption enhancement in thin silicon filmby embedded metallic nanoshells: erratum

Oren Guilatt,1 Boris Apter,2 and Uzi Efron1,2,*1Department of Electro-Optical Engineering, Ben Gurion University, Beer-Sheva, Israel

2Department of Electrical Engineering, Holon Institute of Technology, Holon, Israel*Corresponding author: efron@bgu.ac.il

Received March 4, 2011; accepted March 4, 2011 (Doc. ID 142805); published March 29, 2011

In a previous Letter [Opt. Lett. 35, 1139 (2010)], overestimated values of absorption enhancement were presented.Here, we present the results corrected by factors between 0.82 and 0.24. © 2011 Optical Society of AmericaOCIS codes: 350.6050, 240.6680, 040.5350, 160.5140.

Following the release of our Letter [1], it was found thatthe absorption results described were affected by an fi-nite-difference time-domain computation error. Becauseof discretization of both the electromagnetic field and thedielectric functions, when intense electromagnetic fieldis present at the interface between two materials witha large difference in their absorption coefficients, signif-icant absorption errors may occur at the boundary pixels.This phenomenon may dominate the absorption calcula-tion in the case of localized surface plasmon resonancesimulated in minute structures, as used in our research.In our case, we found that this error has significantlyamplified our absorption results. We have subsequentlyperformed a modified simulation based on an updatedversion of FullWAVE [2] issued by Rsoft Co. upon ourrequest. In this updated version, an option was addedto allow the elimination of the absorption in the interfa-cial layer where the dielectric function was erroneouslycalculated in previous software versions by averaging thetwo materials.The corrected absorption enhancement results, along

with the originally published results (Fig. 3 in [1]) for a

40 nm diameter, 4-nm-thick nanoshell, are shown inTable 1.

While still exhibiting a sizable absorption enhance-ment, it can be seen that the original absorption enhance-ment is now significantly reduced. Thus, as an example,the enhancement in the 750–1000 nm region is down to3:67∶1 from the original value of 15:12∶1, shown inFig. 3 of [1].

References

1. O. Guilatt, B. Apter, and U. Efron, Opt. Lett. 35, 1139 (2010).2. Rsoft Co., “FullWAVE product overview,” http://rsoftdesign

.com/products.php?sub=Component+Design&itm=FullWAVE.

Table 1. Corrected Absorption Enhancement for a40 nm Diameter, 4-nm-thick Nanoshell

Simulation 300–1000 nm 500–1000nm 750–1000 nm

Original 1:25∶1 6:0∶1 15:12∶1Corrected 1:03∶1 1:91∶1 3:67∶1Correction factor 0.82 0.32 0.24

April 1, 2011 / Vol. 36, No. 7 / OPTICS LETTERS 1239

0146-9592/11/071239-01$15.00/0 © 2011 Optical Society of America